如何在特定行或特定单词之后将文本插入文本文件？

Question

I need to create a method that will insert the values passed to it into the body of a index.html file immediately after the first <body> .我需要创建一个方法，将传递给它的值插入到 index.html 文件的正文中，紧跟在第一个<body>之后。

I have the code:我有代码：

class New_class

  def status(sourse, hp, sleep)

    @sourse = sourse

    File.open(@sourse, 'a'){ |file| file.puts  hp, sleep }

  end
end

tamgem = New_class.new

tamgem.status("index.html", 20, 20)

How can I make sure the numbers that I pass to this method are inserted into the body of the HTML document?如何确保传递给此方法的数字插入到 HTML 文档的正文中？ Also, please note that this is a only Ruby, not Rails.另外，请注意，这只是 Ruby，不是 Rails。

Answer 1

You can make a method like this:您可以制作这样的方法：

def write_after_body(original_file, new_file, *new_content)
  File.open(new_file, 'w') do |file|
    IO.foreach(original_file) do |line|
      file.write(line)
      if line.include? '<body>'
        file.write(*new_content)
      end
    end
  end
end

It will leave the original file unchanged and create a new file with the changes you want because reading and writing from and to the same file at the same time isn't really a good idea.它将保持原始文件不变，并使用您想要的更改创建一个新文件，因为同时读取和写入同一个文件并不是一个好主意。 Calling the method like this:像这样调用方法：

write_after_body("index.html", "new_index.html", 20," ", 20)

Will copy all the content from the original file index.html to the new file new_index.html and also add 20 , " " and 20 to a new line after the <body> tag.将原始文件index.html中的所有内容复制到新文件new_index.html中，并在<body>标记后的新行中添加20 、 " "和20 。 After that, if you're happy with the results you can delete/move the old file and rename the new file.之后，如果您对结果感到满意，您可以删除/移动旧文件并重命名新文件。

Answer 2

Parsing HTML with regular expressions or any other primitive means like StringScanner is seldom a good idea .用正则表达式或任何其他原始方法（如 StringScanner）解析 HTML很少是一个好主意。 Instead use a HTML parser ( nokogiri ) that actually understands HTML.而是使用实际理解 HTML 的 HTML 解析器 ( nokogiri )。

require 'nokogiri'
@doc = Nokogiri::HTML('<html><body></body></html>')
@doc.at('body').add_child('<h1>Hello World</h1>')
@doc.to_html
# => "<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.0 Transitional//EN\" \"http://www.w3.org/TR/REC-html40/loose.dtd\">\n<html><body><h1>Hello World</h1></body></html>\n"

Answer 3

Ruby has a built-in class called StringScanner , which can be used as a convenient way to find a position of some pattern inside of a string. Ruby 有一个内置的 class 称为StringScanner ，它可以作为一种方便的方法来查找字符串中某些模式的 position。

Why could this be useful in your case?为什么这对您的情况有用？ You can try to find the index of the first character after the <body> tag.您可以尝试查找<body>标签后的第一个字符的索引。

Knowing that index, you can easily insert a substring into the correct place in your HTML.知道该索引后，您可以轻松地将 substring 插入 HTML 的正确位置。

Here is an example:这是一个例子：

<!-- index.html -->

<!DOCTYPE html>
<html>
<head>
  <title>Page Title</title>
</head>
<body>
  <h1>This is a Heading</h1>
  <p>This is a paragraph</p>
</body>
</html>

# Ruby script in the same folder as `index.html`.

# Library where StringScanner is located.
require 'strscan'

# Read all content of `index.html` and store it into a variable.
html = File.read('index.html')

# Create the StringScanner instance.
scanner = StringScanner.new(html)

# Then you are scanning your HTML string until the first occurence of the <body> tag.
scanner.scan_until(/<body>/)

# If your search is successful,
# then the scan pointer position will be just beyond the last character of the match.
# 
# In other words,
# the scan pointer position will be the index of the first character after `<body>` tag.
index = scanner.pos

# Simple insert
updated_html = html.insert(index, "\nHello")

# Write updated content to `index.html`.
File.write('index.html', updated_html)

So, probably your class will look like the following:因此，您的 class 可能如下所示：

require 'strscan'

class New_class
  def status(source, hp, sleep)
    html = File.read(source)

    scanner = StringScanner.new(html)

    scanner.scan_until(/<body>/)

    index = scanner.pos

    updated_html = html.insert(index, "#{hp} #{sleep}")

    File.write(source, updated_html)
  end
end

tamgem = New_class.new

tamgem.status("index.html", 20, 20)

As a last note: If you don't have any special requirements, please use CamelCase for class names as it is suggested by the majority of Ruby style guides.最后一点：如果您没有任何特殊要求，请使用 CamelCase 作为 class 名称，因为大多数 Ruby 样式指南都建议使用 CamelCase。 Here are some examples: Rubocop , Airbnb .以下是一些示例： Rubocop 、 Airbnb 。

Sources:资料来源：

StringScanner 字符串扫描仪
String#insert 字符串#插入
File.read文件读取
File.write文件写入
CamelCase Classes by Rubocop Rubocop 的 CamelCase 类
CamelCase Classes by Airbnb Airbnb 的 CamelCase 课程

After reading this article看完这篇文章

Update更新

I agree, in general, it is not a good idea to use regular expressions to parse HTML , so when a problem is relatively simple you can use the approach described above, but if you need something more comprehensive, please refer to @max answer .我同意，一般来说，使用正则表达式来解析 HTML 并不是一个好主意，所以当问题相对简单的时候你可以使用上面描述的方法，但是如果你需要更全面的东西，请参考@max answer 。

如何在特定行或特定单词之后将文本插入文本文件？

问题描述

3 个解决方案

解决方案1
1 2019-10-25 15:20:51

解决方案2
1 已采纳 2019-10-27 00:00:56

解决方案3
0 2019-10-26 00:10:04

Update更新

如何在特定行或特定单词之后将文本插入文本文件？

问题描述

3 个解决方案

解决方案1 1 2019-10-25 15:20:51

解决方案2 1 已采纳 2019-10-27 00:00:56

解决方案3 0 2019-10-26 00:10:04

Update更新

解决方案1
1 2019-10-25 15:20:51

解决方案2
1 已采纳 2019-10-27 00:00:56

解决方案3
0 2019-10-26 00:10:04